三峡水库汛期“蓄清排浑”动态运用方式计算研究

Calculation and Study on Dynamic Operation Mode of “Storing Clear Water and Releasing Muddy Water” in the Three Gorges Reservoir in Flood Season

在入库沙量大幅减少的背景下,三峡水库持续开展汛期中小洪水调度,增大了汛期库区泥沙淤积和防洪风险,减少了水库下泄大流量的机会。在三峡水库汛期,开展“蓄清排浑”泥沙调度方式动态运用研究有助于进一步优化三峡水库汛期调度方式。利用三峡水库干支流河道一维非恒定流数学模型,探索开展了三峡水库汛期“蓄清排浑”动态运用方式计算研究,并提出了汛期“蓄清排浑”动态运用方案。计算结果表明:三峡水库汛期“蓄清排浑”动态运用方式可以同时兼顾排沙、发电和防洪,“蓄清”水位150m要优于155m,“蓄清”运行期间库水位可选择在145~150m之间浮动运行;建议将寸滩含沙量达到2.0kg/m3且当日寸滩站入库流量≥25000m3/s的时间作为水库增泄“排浑”的起始时间,将出库含沙量降至约0.1kg/m3作为“排浑”调度结束重新进入“蓄清”调度的泥沙参考因素。研究成果可为三峡水库汛期优化调度提供参考。

Under the background of a large reduction in the sediment into the Three Gorges Reservoir(TGR),dispatching of medium-and-small-scale flood in flood season has exacerbated the risks of sediment deposition and flood control in TGR and reduced the chances of large discharge of the reservoir.Studying the dynamic dispatching of"storing clear water and releasing muddy water"in flood season is conducive to further optimizing the dispatching mode.Using one-dimensional unsteady flow mathematical model of the mainstream and tributaries of TGR,we put forward the dynamic operation scheme of"storing clear water and releasing muddy water"in flood season of TGR through calculations.The calculation results illustrate that the dynamic operation mode of"storing clear water and releasing muddy water"in flood season takes into account both sediment discharge,power generation and flood control.A water level at 150 m when"storing clear water"is superior to 155 m;the water level can fluctuate between 145 m and 150 m in the period of"storing clear water".We recommend to start the releasing of muddy water when the sediment concentration of Cuntan station reaches 2.0 kg/m^3 and meanwhile the incoming flow of Cuntan station on that day exceeds 25000 m^3/s;on the contrary,when the sediment concentration of Cuntan station falls to about 0.1 kg/m^3,we suggest to end the releasing of muddy water and begin to store clear water.The research findings provide reference for the optimal operation of TGR in flood season.